account billing bought charged completly date few listing next pay payment product short spend subscription update upgrade upgraded

I just upgraded to a $10 subscription. How do I upgrade to a $15 subscription? I don't want to spend another $15, just add $5 to what I just bought. I am a few MB short of completly listing my product line.

You don't pay when you update the subscription, you are only charged the new payment account on the next billing date.